X4 for OSX vs. X3 as a bibliographic tool--reasons to upgrade?

I’m curious what the general impression is of people who have migrated over to X4 from X3. I can’t see huge advantages from the literature on X4, outside of PDF enhancements (which don’t interest me all that much). Are there truly more and improved features from X3? Is this a must-have upgrade?

many thanks in advance, Jim P.

I can only comment on the windows version.  Between x3 and x4, I like the searching of pdfs (but you indicated that wasn’t enough) there is now the wildcard use in search/retrieval, the ability to hyperlink citations to references in word documents, improved footnote handling (if you need that sort thing) and a big plus is that when a ref is in the traveling library, it seems to be able to find a match in the endnote library even if the record number has changed.  – there are others, but those are the ones that made it a worthwhile difference to me. 

Thanks. I may give it a trial. I do hope that X3 will be compatible with Word 2011; and that if I try X4 my library will be backwards compatible with X3 if I go back.

Being able to search PDFs on X4 isn’t that big of a deal for Mac users because we have for a long time been able to search the contents of most documents via the built-in Spotlight function.

I was just trying out the trial version of X4 for Macs and I don’t see any great new functions to upgrade. Sure, getting Word 2010 compatibility is great, but to get that at the price of $115 for upgrade is too steep.